Answer:
Option (d) is correct.
Explanation:
Materials cost = $310
Labor cost = Labor hours × Wages per hour
         = 20 hours × $11
         = $220
Overhead cost = Overhead for each employee hour × Labor hours
             = $17 × 20 hours
             = $340
Total cost = Materials cost + Â Labor cost + Overhead cost
        = $310 + $220 + $340
        = $870
Hence, correct answer is $870.